Part of the spectrum centered about 700 MHz is allocated for public use. Normally, public use calls are established, conducted, and terminated without interruption. However, during emergency situations, the available bandwidth may become fully used. In such a situation, some “priority” users may be able to terminate an existing call by preemption. During preemption, any call may be terminated to allow a “high priority” user to conduct a call. Even users who have a pre-established call priority level may have their calls preempted by higher priority users. Yet, some pre-established priority level calls are of such importance that they should not be terminated by higher priority calls. Such calls may include calls whose premature termination can result in a greater hazard because of the premature termination. Today, no method of changing call priority exists for an active call in the 700 MHz band or any other public use frequency band.